earticle

영어

Thermoacidophilic archaea such as Thermoplasma acidophilum and Sulfolobus solfataricus metabolize Dglucose via the non‐phosphorylated metabolic pathway (NMP), an ED‐like pathway in which aldose intermediates are not phosphorylated. The first step of the non‐phosphorylated glycolysis pathway is the oxidation of D‐glucose to D‐gluconate, catalyzed by NADP‐dependent D‐glucose dehydrogenase. DGluconate is then dehydrated by D‐gluconate dehydratase to 2‐keto‐3‐deoxy‐D‐gluconate (KDG), which undergoes an aldolate cleavage to pyruvate and D‐glyceraldehyde by KDG aldolase. During the last ten years we investigated the NMPs in T. acidophilum and S. solfataricus and identified the genes involved in archaeal NMPs. Recently we have also found that oligotrophic marine bacteria metabolize D‐glucose, D‐galactose, Dxylose, L‐arabinose and D‐fucose via the novel NMP where the downstream pathway is different from the previously known NMPs. A BLAST search of the GenBank database has revealed that proteins homologous to the NMP enzymes are present in all three phylogenetic domains of life (Archaea, Bacteria, and Eukarya), which may indicate possible advantages of the non‐phosphorylated metabolic system under oligotrophic or starved conditions. This presentation will review our current understanding of the NMP system in natural environments and our recent progress in the application of the NMP system to the production of bioproducts such as biofuels and bioplastics.